Synthesis of a Hydroxyapatite Nanopowder via Ultrasound Irradiation from Calcium Hydroxide Powders for Potential Biomedical Applications

Nanoscale hydroxyapatite based ceramics are a relatively new form of materials that are currently being investigated for a number of potential biomedical applications. This study reports on a straightforward wet chemical method that uses calcium hydroxide and phosphoric acid as precursors. After chemical synthesis a conventional thermal treatment was used to produce an ultrafine hydroxyapatite nanopowder. Varying ultrasonic power between zero and 400 W during the synthesis process produced crystallite sizes ranging from 15.4 nm down to 12.2 nm. The morphology of particles synthesized under the influence of ultrasonic irradiation was predominantly spherical and granular. Also present were a small number of irregular shaped plates. Energy dispersive spectroscopy revealed the samples had a Ca:P ratio of 1.66, which was very close to the ideal value of 1.67. FT-IR studies identified functional groups and confirmed the results of the X-ray diffraction data that the powders were indeed composed of nanoscale hydroxyapatite.